Approach to a fungal treatment of a biologically treated landfill leachate. (15th November 2022) - Díaz, Ana Isabel
Abstract: White-rot fungi (WRF) have the ability to synthetize extracellular enzymes that could degrade recalcitrant pollutants. The aim of this work was to evaluate the use of P. chrysosporium to treat a biologically and physically pre-treated landfill leachate which high load of refractory compounds (COD>1000 mg/L, BOD5 <50 mg/L) in order to reduce COD and colour. Batch tests were carried out at 26 °C and 135 rpm for 15 days. The soluble chemical oxygen demand (sCOD), soluble biological oxygen demand (sBOD5 ) and colour, as well as the lignin peroxidase (LiP) and manganese peroxidase (MnP) enzymatic activities were analysed. Besides, the effects of different operating conditions, i.e., pH control, permeate dilution and supplementation, on treatment efficacy were investigated. The control of pH was shown to be key for fungal treatment. In addition, it was found that the addition of carbon and nitrogen sources improved the enzymatic synthesis and the removals of sCOD and colour. Data here obtained open the possibility of using fungi for reducing the amount of recalcitrant pollutants still present in treated landfill leachates or similar effluents. Graphical abstract: Image 1 Highlights: Potential of P. chrysosporium to treat a biologically pretreated leachate is shown. Addition of carbon and nitrogen and pH control were key to enhance enzyme synthesis. A 5 g/L concentration of glucose decreased the efficacy of the fungal treatment. At best, removals of about 40% were achieved for colour and soluble COD. Fungal treatment has proven to be a hopeful method for highly recalcitrant leachate.